SiCOH film preparation using precursors with built-in porogen functionality

Abstract

A method of fabricating a dielectric material that has an ultra low dielectric constant (or ultra low k) using at least one organosilicon precursor is described. The organosilicon precursor employed in the present invention includes a molecule containing both an Si—O structure and a sacrificial organic group, as a leaving group. The use of an organosilicon precursor containing a molecular scale sacrificial leaving group enables control of the pore size at the nanometer scale, control of the compositional and structural uniformity and simplifies the manufacturing process. Moreover, fabrication of a dielectric film from a single precursor enables better control of the final porosity in the film and a narrower pore size distribution resulting in better mechanical properties at the same value of dielectric constant.

Description

RELATED APPLICATIONS [0001] The present application is related to co-assigned U.S. application Ser. No. 10 / 964,254, filed Oct. 13, 2004, entitled “ULTRA LOW k PLASMA ENHANCED CHEMICAL VAPOR DEPOSITION PROCESSES USING A SINGLE BIFUNCTIONAL PRECURSOR CONTAINING BOTH A SiCOH MATRIX FUNCTIONALITY AND ORGANIC POROGEN FUNCTIONALITY”, the entire contents of which is incorporated herein by reference.FIELD OF THE INVENTION [0002] The present invention generally relates to a method of fabricating a dielectric material that has an ultra low dielectric constant (or ultra low k) using at least one organosilicon precursor. The organosilicon precursor employed in the present invention includes a molecule containing both an Si—O structure and a sacrificial organic group, as a leaving group. The use of an organosilicon precursor containing a molecular scale sacrificial leaving group enables control of the pore size at the nanometer scale, control of the compositional and structural uniformity and si...

AI Technical Summary

Benefits of technology

[0013] More specifically, the present invention describes methods for fabricating a layer of a SiCOH dielectric material having improved film properties, which is uniform in atomic and structural composition, both when measured across the substrate diameter, and through the depth of the layer, that does not exhibit variation in the process or process instability. Further, the dielectric films of the present invention have a pore size on the nanometer scale without the presence of larger pores, and hence the distribution of pores sizes is uniform and narrow.

[0014] The use of the inventive methods with deposition of a preliminary film from one or more, preferably a single, organosilicon precursors containing a built-in sacrificial organic porogen enables better control of the porosity in the final film and a narrower pore size distribution, resulting in better mechanical properties at the same values of dielectric constant. Furthermore, the deposition of a preliminary film from the organosilicon precursors described herein enables improved mechanical properties of the final SiCOH dielectric film.

Problems solved by technology

This combined effect increases signal delays in ULSI electronic devices.

Most commercially available dielectric materials, however, are not thermally stable when exposed to temperatures above 300° C. Integration of low k dielectrics in present ULSI chips requires a thermal stability of at least 400° C.

It is also commonly found that SiCOH dielectrics made in the prior art from two or more separate organosilicon and / or porogen molecules are not uniform in atomic and structural composition, both when measured across the substrate diameter, and through the depth of the dielectric layer.

The use of 300 mm Si wafers has made this problem of chemical uniformity across the wafer more pronounced.

Additionally, prior art CVD SiCOH dielectrics made from two or more separate organosilicon and / or porogen molecules were found to exhibit process variation or process instability due to small changes in the flow rate of one of the two precursors, known to those skilled in the art as drift in the flow rate.

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